The purpose of this grant proposal is to conduct a longitudinal descriptive investigation designed to test a multidimensional model for symptom interpretation using breathlessness as the phenomenon of interest. The specific aims are to: (1) establish reliability and validity of two instruments proposed to measure symptom interpretation and dimensionality with breathlessness, (2) test and modify a model of symptom interpretation known as the Symptom Interpretation Model (SIM), and, (3) refine the definition and improve understanding of the symptom interpretation process and breathlessness. Pathological breathlessness (dyspnea) is the most common symptomatic complaint of individuals with chronic obstructive pulmonary disease (COPD) and frequently is a key factor in seeking emergent care. During 1988, COPD and its allied conditions accounted for over 84,000 deaths and 704,000 hospitalizations in the United States (U.S. Department of Health and Human Services [USDHHS], 1989). The financial impact of these numbers is estimated to be 10.4 billion dollars in direct costs alone. Despite the prevalence and seriousness of breathlessness, definition and measurement are inadequate. The associated symptom interpretation process has received minimal investigation despite reports of growing numbers of individuals experiencing the symptom. The SIM proposes that cognitive factors, such as past symptom judgments and knowledge, largely determine interpretation. Testing of the model will allow for verification as to the influence of past symptom experiences on present situations. The investigational design will enhance generalizability of the findings through a heterogeneous sample consisting of healthy individuals, asthmatics, and those with COPD. Examination of the three groups, which have very different experiences with breathlessness, will provide critical information not previously considered. This research will capture relevant but evolving subject information such as fluctuations in peak flow and symptom intensity. This investigation will allow for enhanced understanding of the process by which thousands of individuals determine that they are breathless and in so doing illuminate nursing intervention strategies that will decrease the financial, physical, and emotional impact.